L044026068

Krishna Aditya Y V Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 4( Version 2), April 2014, pp.60-68
www.ijera.com 60 | P a g e
Study of change in mechanical properties of Zr2, Zr4, INCOLOY
800 and D9 materials on pilgering
Krishna Aditya Y V
Department of mechanical engineering, SRM University, kattankulathur, Chennai-603203
ABSTRACT
Zr2, Zr4, INCOLOY 800 and D9 are successfully used for cladding materials because of their mechanical and
neurotic properties. Appropriate manufacturing process has to be chosen for these materials to precise control
their mechanical properties. In this study cold working process of pilgering is chosen and the study of
mechanical properties for the materials taken with prior cold work and further cold worked by pilgering route
were characterized through tensile and hardness testing. While cold working Yield Strength, Ultimate Tensile
Strength & Hardness increases due to work hardening but % elongation decreases due to work hardening which
implies that ductility of material is reduced.
Keywords - annealing, cold-working, hardness, pilgering, tensile
I. Introduction
1.1 Different types of tubes and sections required for nuclear reactors
The materials are selected for reactor use considering the severe environment of neutron flux, neutron
economy considerations, high temperature strength, corrosion resistance etc. Zirconium alloys are [1-7] used in
PHWRS and BWRS while D9 Tubes are used in FAST BREEDER REACTORS [8-9]. Incoloy 800 tubes are
used as heat exchanger tubes for steam generators of PHWRS. Circular, square and hexagonal sections in
various sizes, manufactured by exotic materials meeting special requirements are required for different reactors.
Fig.1. Different types of tubes and sections required for nuclear reactors
1.2 Process route for manufacture of pilgeredtubes[10]
Fig: 2. Process route for manufacture of pilgered tubes
BILLET
PREPARATION
EXPANSION EXTRUSION DEJACKETING/
DEGLASSING
BLANK
CONDITIONING
PILGERINGDEGREASINGANNEALINGSTRAIGHTENING
INSPECTION
&TESTING
FINSIHING OPERATIONS
RESEARCH ARTICLE OPEN ACCESS

II. Experimental
2.1 Composition of materials taken
Table.1. Composition of materials taken
Grade Zr4 Zr2 D9 INC800
Base
metal
Zr(Zirconium)-
98%
Zr(Zirconium)-
98%
Fe (Iron)-71% Fe (Iron)-48%
Alloying
elements
Fe(Iron) 0.22% 0.10% Shown above Shown above
Cr
(Chromium)
0.10% 0.10% 13.5-14.5% 20%
Ni(Nickel) - 0.05% 14.5-15.1% 32%
C(Carbon) 150 to 400ppm 150 to 400ppm 0.05 %max 0.03%
Sn(Tin) 1.3% 1.5% - -
Mn
(Manganese)
- - 2% -
Mo
(Molybdenum)
- - 2.5% -
Ti(Titanium) - - 0.25% -
Each of Zr2, Zr4, INCOLOY-800, and D9 tubes which were prior cold worked are taken in annealed and
pilgered conditions.
Firstly, prior cold works of the materials taken are calculated. Then, to study the changes in mechanical
properties of the materials taken, tensile and hardness tests are performed and results were obtained. Finally the
changes are depicted in the form of graphs and conclusions were made from analysing the results.

2.2 Tube material dimensions
Table.2 Tube material dimensions
Tube
materials
taken
Zr2 Zr4 INCOLOY 800 Alloy D9
Condition Annealed Pilgered Annealed Pilgered Annealed Pilgered Annealed pilgered
G –
Gauge
length
[N1]
50.8 50.8 50.8 50.8 95 95 40 45
OD-
Outer
diameter
21 14.6 17.1 15.2 19.6 19 19.6 21.4
T-
Thickness
2.2 0.9 1.0 0.4 1.0 1.1 1 0.7
NOTE: All dimensions are in mm
2.3 Standard values of materials taken
Table.3. Standard values of materials taken
Specimen Zr2 Zr4 INCOLOY
800
D 9
Tensile strength ,
Yield 0.2% Ksi
34.9 34 39.8 79.7
Tensile strength,
ultimate, Ksi
59.9 59 87 101
HRB 99.8 89 81 96
% elongation 20 20 45 20
2.4 Calculation of prior cold work[N2]
2.4.1 Cold work
The amount of cold work is defined relative to the reduction in cross-sectional area or thickness of the metal by
processes such as rolling or drawing.

Fig: 2 Diagram representing cross-sectional areas of tubes before and after pilgering.
The amount of cold work can be calculated as follows
%CW = [(Ao - ao)/A0] x 100%
= [(DoWo-dowo)/DoWo] x 100%
Table. 4 cold work calculation
Tube material Zr2 Zr4 INCOLOY 800 D9
Prior cold work (%) 71 63 3 20
2.5 Tensile testing
Tensile testing, also known as tension testing, is a fundamental materials sciencetest in which a sample is
subjected to a controlled tensionuntil failure. The results from the test are commonly used to select a material
for an application, for quality control, and to predict how a material will react under other types of forces.
Properties that are directly measured via a tensile test are ultimate tensile strength, maximum elongationand
reduction in area. From these measurements the following properties can also be determined: Young's
modulus,yield strength, and strain-hardeningcharacteristics.
2.5.1 Test specimen nomenclature

Fig: 3 Test specimen nomenclatures
2.5.2 Standard used for tensile testing of tubes
ASTME8 / E8M-11: "Standard Test Methods for Tension Testing of Metallic Materials"
2.6 Hardness test
Rockwell Hardness test B (HRB) test is used here as these materials are annealed carbon steels.
2.6.1 Standard used for hardness (HRB) testing of tubes
ASTM E18: “Standard Test Methods for Rockwell Hardness of Metallic Materials”
3. Result
Stress-strain curves obtained from tensile testing of materials are attached in the annexure. Values obtained
from tensile and hardness tests at annealed and pilgered conditions are tabulated below.
Table.5 Result
Material Sample
no.
Size Condition Hardness
(HRB)
YS
(Ksi)
UTS
(Ksi)
%EL[N3]
Zr2 8 21 x
2.2
Annealed 91 56.4 79.7 35.0
1 14.6 x
0.9
71% cold work
pilgered from 21
x 2.2
94.5 69.34 89.94 24.0
Zr4 2 17.1 x
1.0
Annealed 78.5 50.44 71.83 44.0
3 15.2 x
0.4
63% cold work
pilgered from
17.1 x 1.0
87.5 97.99 107.98 24.0
Incoloy
800
4 19.6 x
1.0
Annealed 75.25 39.80 88.19 37.0
5 19 x
1.1
3% cold work
pilgered from
19.6 x 1.0
78.25 55.90 90.89 31.0
D9 6 19.6 x
1
Annealed 76.75 36.95 87.56 50.0
7 21.4 x
0.7
20% cold work
pilgered from
23.5 x 0.8
88.75 101.3 107.8 25.0
4. Graphs

4.1.1 Consolidation of variation in YS for Zr2, Zr4, INCOLOY 800 and D9 atAnnealed and pilgered
conditions
4.1.2 Consolidation of variation in UTS for Zr2, Zr4, INCOLOY 800, D9 atAnnealed and pilgered
conditions
ANNEALED PILGERED
Zr2 79.7 89.94
Zr4 71.83 107.98
INC 800 88.19 90.89
D9 87.56 107.8
79.7
89.94
71.83
98
88.19 90.89
87.56
107.8
0
20
40
60
80
100
120
KSI
Zr2
Zr4
INC 800
D9
ANNEALED PILGERED
Zr2 56.4 69.34
Zr4 50.44 97.99
INC 800 39.8 55.9
D9 36.95 101.3
56.4
69.34
50.44
97.99
39.8
55.9
36.95
101.3
0
20
40
60
80
100
120
KSI
Zr2
Zr4
INC 800
D9

4.1.3 Consolidation of variation in %ELONGATION for Zr2, Zr4, INCOLOY800, D9 at annealed and
pilgered condition
4.1.4 Consolidation of variation in HARDNESS for Zr2, Zr4, INCOLOY800, and D9 atannealed and
pilgered condition
5. Discussion
Since pilgering is a complex process, there is a lot of scope for study and carrying out analysis. Some of those
are:
• Characteristics of different materials.
• Study on work hardening.
ANNEALED PILGERED
Zr2 91 94.5
Zr4 78.5 87.5
INC 800 75.25 78.25
D9 76.75 88.75
0
10
20
30
40
50
60
70
80
90
100
HRB
Zr2
Zr4
INC 800
D9
ANNEALED PILGERED
Zr2 35 24
Zr4 44 24
INC 800 37 31
D9 50 25
35
44
24
37
31
50
25
0
10
20
30
40
50
60
%e
Zr2
Zr4
INC 800
D9

• Kinematic study of pilgermills.
• Force calculations.
• Tribological studies.
• Spring back aspects.
• Metallurgical and micro structural studies.
Conclusions
Samples of Zr4, Zr2, D9, and INC800 were taken for tensile test & hardness test. Recorded values were
tabulated and following observations were made.
1) While cold working YS, UTS& hardness increases due to work hardening.
2) % elongation decreases due to work hardening which implies that ductility of material is reduced.
3) This is in line with the theory of deformation. From the above the formability of material substantially
reduces with the increase in cold work, there-by sizing / shaping of the material will not be possible.
Thus intermediate annealing is carried out to regain its ductility & for further cold working.
References
[1] R.J. Puigh, M.L. Hamilton, in: F.A. Garner, C.H. Henager Jr., N. Igata (Eds.), Influence of Radiation
on Material Properties Part II, STP, 956, ASTM, Philadelphia, PA, 1989, p. 22.
[2] D.L. Smith, J. Nucl. Mater. 122 (1984) 51.
[3] W. Kesternich, J. Rothaut, J. Nucl. Mater. 104 (1981) 845.
[4] D.R. Harries, Nucl. Energy 17 (1978) 301.
[5] T . I ka i, S. Y uhar a,I. S hib ara , H. K ubo ta , M. Ito h, S. Nomura, Proceeding of the
International Conference on Materials for Nuclear Reactor Core Applications,
BNES,London, 1987, p. 203.
[6] A K Suri,Material development for India’s nuclear power programme, Indian Academy of Sciences,
Sadhana Vol. 38, Part 5, October 2013, pp. 859–895.
[7] Zirconium in the Nuclear Industry, Twelfth International Symposium, Issue 1354.
[8] S.L. Mannan, S.C. Chetal, Baldev Raj, S.B. Bhoje, Selection of materials for prototype fast breeder
reactor ,Transactions of the Indian Institute of Metals, 56 (2) (2003), pp. 155–178.
[9] K.G. Samuel , S.K. Ray, G. Sasikala, Dynamic strain ageing in prior cold worked 15Cr–15Ni titanium
modified stainless steel (Alloy D9, Journal of Nuclear Materials, Volume 355, Issue 1-3, p. 30-37.
[10] Hideaki Abea, Munekatsu Furugenb, Journal of Materials Processing Technology / Volume 212 /
issue 8.
8. Notes
[1] Gauge length calculation
For Zr2 and Zr4: 50.8 mm
For incoloy 800: 5d = 95 mm
For D9:5.65 A = (5.65 19.6 − 1 1π) = 45 mm
For D9: 5.65 A = (5.65 21.4 − 0.7 0.7π) = 40 mm
[2] % CW
[3] % e calculation
Sample no.1

Sample no: 2:
Sample no: 3:
Sample no: 4:
Sample no: 5:
Sample no: 6:
Sample no: 7:
Sample no: 8:

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